A mechanical seal generally comprises a rotating member attached to a pump shaft and a stationary member attached to a pump housing. The rotating member is in direct contact with the stationary member, which provides the seal. Both the rotating member and the stationary member are commonly referred to in the mechanical sealing industry as seal ‘faces’. A basic operating principle of mechanical seals is that the seal faces require a ‘fluid film’ that provides a lubricant between them in order to function correctly.
Applying a synthetic diamond coating to the seal faces can aid in the performance of the mechanical seal in various different applications.
To apply a synthetic diamond coating to mechanical seal faces a coating chamber is used. The mechanical seal faces are placed inside the coating chamber with the surface to be coated facing outwards from the centre of the coating chamber. A jig like device is generally provided to support the mechanical seal face within a recess provided within a part of the jig. The recess is defined by one or more elements of the jig. It has been found that the coating applied to a mechanical seal face located in a jig is typically of varying evenness and in particular tends to increase in depth at the outer edge of the seal face. This is undesirable; a uniformly even coating is required. It has been reported in the industry that applying a synthetic diamond coating to the seal faces aids in the performance of the mechanical seal in various differing applications.
To apply a synthetic diamond coating to mechanical seal faces, a coating chamber is used. The mechanical seal faces are placed inside the coating chamber with the chosen surface that is to be coated facing outwards from the centre of the coating chamber.
It is generally accepted that the coating chamber is charged at a fixed rate per cycle of synthetic diamond coating applied. Therefore the greater number of mechanical seal faces that can be placed in each cycle run, the higher is the cost efficiency which can be achieved per seal face.
The nature of mechanical seal faces is that they are available in various different sizes and heights, and, as they are all of circular geometry, they are very inefficient on space. This causes a problem in creating a fixture to hold the mechanical seal faces in the coating chamber. Solutions aimed at solving this problem involve creating a special fixture per seal face that is to be coated. However this causes large inefficiencies of time and cost. Also potentially thousands of specially created fixtures are required for the many different sizes of mechanical seal faces that might go through the synthetic diamond coating cycle.